Pressure compensation device for a housing of an electrochemical device

ABSTRACT

A pressure compensation device for compensating an internal pressure in a housing of an electrochemical device is provided, including at least one gas through-opening and at least one membrane element with a gas-permeable membrane, which is deformable depending on a change in the internal pressure and by which the gas through-opening is blocked, and a protective degassing element, which is configured and arranged in such a way that when a critical deformation of the membrane is reached, it damages the membrane in such a way that the membrane at least partially opens the gas through-opening for protective degassing of the housing. The pressure compensation device allows both reliable pressure compensation between the interior of the housing and the exterior of the housing of an electrochemical device during normal operation of the electrochemical device and also ensures reliable bursting protection in the event of excess internal pressure in the housing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from, and the benefit under 35 U.S.C. §119, of German Patent Application No. 10 2011 080 325.4, filed Aug. 3, 2011, which is incorporated herein by reference in its entirety and for all purposes.

FIELD OF DISCLOSURE

The present invention relates to a compensation device for compensating an internal pressure in a housing of an electrochemical device, the pressure compensation comprising at least one gas through-opening and at least one membrane element with a gas-permeable membrane, which is deformable depending on a change in the internal pressure and by which the gas through-opening is blocked.

BACKGROUND OF THE INVENTION

Closed containers with a large internal volume and a thin wall cannot be completely hermetically sealed relative to the external wall. In order to prevent the housing of the container bursting or bulging, a continuous air exchange with the environment is necessary. Nevertheless, the interior of the housing is to be protected from penetrating dirt and water.

Pressure compensation devices for such housings of the type mentioned at the outset are therefore known, which comprise membranes or films having a certain gas permeability, in particular air permeability, but also a seal against water.

If an excess pressure occurs within the housing within a short time, for example upon the failure of a battery cell within an energy store housing, this critical pressure has to be able to be rapidly reduced to prevent damage to the housing.

In order to realize protection of this type for the housing against bursting, it is known to insert bursting discs, in particular made of a metallic sheet material, or safety flaps or valves into the housing wall.

SUMMARY OF THE INVENTION

The present invention is based on the object of providing a pressure compensation device of the type mentioned at the outset, which allows both reliable pressure compensation between the interior of the housing and the exterior of the housing of an electrochemical device during normal operation of the electrochemical device and also ensures reliable bursting protection in the event of excess internal pressure in the housing, the pressure compensation device being simply constructed and easily producible.

This object is achieved according to the invention in a pressure compensation device having the features of the preamble of claim 1 in that the pressure compensation device comprises a protective degassing element, which is configured and arranged in such a way that when a critical deformation of the membrane is reached, it damages the membrane in such a way that the membrane at least partially opens the gas through-opening for a protective degassing of the housing.

The solution according to the invention is therefore based on the idea of combining the functions of pressure compensation and protective degassing for the housing of the electrochemical device, with simultaneously high resistance relative to a high water pressure exterior to the housing, in one and the same component.

The use of a stable, but porous and therefore gas-permeable membrane fulfils the pressure compensation function and the protection of the interior of the housing from penetrating water and dirt during normal operation of the electrochemical device.

The use of a protective degassing element, for example in the form of a protective degassing spike, which adds a predetermined rupture point to the porous membrane, leading to the desired failure of the membrane in the event of a pressure increase up to a critical pressure, ensures the required bursting protection for the housing.

In contrast to this, in known devices, two different components are always necessary, namely a first for the pressure compensation during environmentally caused pressure fluctuations during normal operation of the electrochemical device and a second element for the rapid reduction of pressure in the event of an explosion-like increase in the internal pressure in the housing of the electrochemical device. In this case, the first element has to have a certain gas permeability and water pressure resistance for the pressure compensation, and the second element, in the event of a critical pressure increase, has to allow rapid pressure compensation by opening an adequately large gas passage cross-section.

If the element for the pressure compensation is formed as a membrane, which is designed to be so thin that it tears on its own at critical pressure, there is always the danger that a failure of the membrane of this type will not only occur due to loading with a critical internal pressure, but also unintentionally due to water pressure loading from the exterior of the housing.

On the other hand, in the pressure compensation device according to the invention, a membrane with porous properties is used, which has a certain gas permeability to ensure the pressure compensation between the interior and the exterior of the housing, but is designed such that it has an adequate water pressure resistance for protection of the interior of the housing from penetrating dust and water.

The membrane of the pressure compensation device according to the invention does not tear on its own in the event of a critical pressure increase in the interior of the housing, but only when the membrane is damaged by the action of the protective degassing element on the membrane in such a way that the membrane fails within a very short time (within a few milliseconds) following this damage and opens an adequately large cross-section for the protective degassing of the housing.

The protective degassing element may, in particular, be configured as a protective degassing spike, which is preferably stationary or fixed. Owing to loading with an increased internal pressure in the housing of the electromechanical device, the membrane opens toward the protective degassing spike. At a critical excess pressure in the interior of the housing, the membrane impinges on the protective degassing spike, with the protective degassing spike inflicting preliminary damage on the membrane, which leads to the ultimate failure of the membrane within a few milliseconds, so the membrane opens an adequately large cross-section for protective degassing and no longer blocks the gas through-opening of the pressure compensation device.

By adjusting the spacing between the protective degassing element, in particular the protective degassing spike, and the membrane (without a bulge in the rest state of the membrane, in other words when the internal pressure in the housing of the electrochemical device corresponds to the external pressure in the exterior of the housing), the bursting pressure leading to damage of the membrane can be adjusted individually and precisely.

In a preferred configuration of the invention, the membrane comprises a porous plastics material and is preferably substantially completely formed from a porous plastics material of this type.

In particular, it may be provided that the membrane comprises a fluoropolymer material and is preferably substantially completely formed from a fluoropolymer material.

It is particularly favorable if the membrane comprises a polytetrafluoroethylene material and/or a polytetrafluoroethylene compound and is preferably formed substantially completely of one of the materials mentioned.

A polytetrafluoroethylene compound is to be taken to mean here a mixture of a polytetrafluoroethylene material and one or more fillers.

The term polytetrafluoroethylene (PTFE), in this case, also indicates in this description and in the accompanying claims modified polytetrafluoroethylene materials, in which some of the fluorine atoms of the polytetrafluoroethylene are replaced by substituents.

A porous, gas-permeable and water pressure-resistant membrane made of a PTFE material or a PTFE compound may, in particular, be produced in that a granulate of a PTFE material or a PTFE compound is pressed and sintered in a cylindrical or hollow cylindrical mould. A peeled foil is produced from the sintered cylinder or hollow cylinder thus obtained, in that the cylinder or the hollow cylinder is made to carry out a rotary movement and a peeling knife is fed against the lateral surface of the cylinder or hollow cylinder. The membrane can be separated out, in particular cut-out or stamped out, from the peeled film thus obtained.

There are various possibilities for fastening the membrane to the remaining components of the pressure compensation device.

Thus, it may be provided, for example, that the pressure compensation device comprises a carrier element and a clamping element, the membrane element being held by clamping between the carrier element and the clamping element.

In this case, the carrier element and the clamping element are produced separately from one another and preferably releaseably or non-releaseably connected to one another after the arrangement of the membrane element between the carrier element and the clamping element.

For example, it may be provided that the carrier element and the clamping element are integrally connected to one another.

An integral connection of this type may be produced, in particular by welding, in particular laser welding or ultrasonic welding.

Alternatively or in addition to this, it may also be provided that the carrier element and the clamping element are latched to one another.

As an alternative, it may also be provided that the pressure compensation device comprises a carrier element, in the material of which the membrane element is at least partially embedded, in particular at the outer edge of the membrane element.

It may, in particular, be provided that the membrane element has the material of the carrier element injected around it, preferably after being placed in the injection molding tool.

The membrane element may substantially completely consist of the membrane.

The pressure compensation device according to the invention is fixable, preferably releaseably, preferably by means of at least one fastening device, for example by means of at least one fastening screw, to the housing of the electrochemical device.

It may, in particular, be provided for this, that the pressure compensation device has at least one fastening flange with at least one fastening device receiver for a fastening device.

In order to prevent an uncontrolled gas exchange between the interior and the exterior of the housing, past the pressure compensation device, it is advantageous if the pressure compensation device comprises at least one sealing element for the, preferably substantially gas tight, sealing between the pressure compensation device and the housing of the electrochemical device.

A sealing element of this type may, in particular, comprise an elastomer material and preferably be formed substantially completely from an elastomer material.

In particular, the sealing element may comprise an O-ring.

Furthermore, it is favorable if the pressure compensation device comprises at least one protection element, by means of which an outside of the membrane is protected from mechanical damage from outside the pressure compensation device.

A protection element of this type may be, in particular, in the form of a lid or cap.

In order to not impede gas passing through the pressure compensation device, it is favorable if the protection element has at least one gas through-opening, preferably a plurality of gas through-openings.

In order to particularly easily be able to adjust and/or vary the critical bursting pressure, at which the membrane is to fail and open the gas through-opening of the pressure compensation device for a protective degassing of the housing, it is favorable if the pressure compensation device comprises a mechanism for changing the relative position between the protective degassing element and the membrane (in the rest state of the membrane).

A mechanism of this type for changing the relative position may, in particular, comprise an adjusting thread provided on the protective degassing element.

An adjusting thread of this type may, in particular, cooperate with a thread that is complementary thereto on another component of the pressure compensation device, for example on a protection element of the pressure compensation device.

In this case, the adjusting thread of the protective degassing element may be configured as an external thread or an internal thread and the thread that is complementary thereto may be configured accordingly as an internal thread or an external thread.

The pressure compensation device according to the invention is suitable, in particular, for use in an electrochemical device, which comprises a housing, one or more electrochemical cells arranged in the housing and at least one pressure compensation device according to the invention arranged on the housing.

The electrochemical device may, in particular, be configured as a battery, for example as a lithium-ion battery.

If the electrochemical device according to the invention is configured as a battery, it is suitable, in particular, to be a highly loadable energy source, for example to drive motor vehicles.

Further features and advantages of the invention are the subject of the following description and the graphical view of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plan view of a pressure compensation device for compensating the internal pressure in a housing of an electrochemical device;

FIG. 2 shows a schematic longitudinal section through the pressure compensation device from FIG. 1, along the line 2-2 in FIG. 1;

FIG. 3 shows a schematic cross-section through the pressure compensation device from FIG. 1, along the line 3-3 in FIG. 1;

FIG. 4 shows a schematic perspective view of the pressure compensation device from FIGS. 1 to 3;

FIG. 5 shows a schematic side view of the pressure compensation device from FIGS. 1 to 4, with the viewing direction in the direction of the arrow 5 in FIG. 1;

FIG. 6 shows a further schematic side view of the pressure compensation device from FIGS. 1 to 5, with the viewing direction in the direction of the arrow 6 in FIG. 1;

FIG. 7 shows a schematic plan view from below of the pressure compensation device from FIGS. 1 to 6; and

FIG. 8 shows an enlarged view of the region I from FIG. 2 in a second embodiment of the pressure compensation device, which comprises a mechanism for changing the relative position between a protective degassing element of the pressure compensation device and a membrane of the pressure compensation device.

The same or functionally equivalent elements are designated by the same reference numerals in all the figures.

DETAILED DESCRIPTION OF THE INVENTION

An electrochemical device, designated as a whole by 100 and shown schematically as a whole in FIGS. 1 to 7 and, in particular, in FIG. 6 comprises a closed housing 102, in the interior 104 of which a plurality of electrochemical cells 106 are arranged, which may be electrically connected, for example, in series or in parallel.

The housing 102 comprises a housing wall 108, with a, for example, substantially circular, recess 110, which is closed by a pressure compensation device designated as a whole by 112.

As can be seen in particular from the sectional views of FIGS. 2 and 3, the pressure compensation device 112 comprises a carrier element 114, with which the pressure compensation device 112 abuts in the assembled state on the housing wall 108; a membrane element 116, which rests on a membrane element seat 118 of the carrier element 114; a clamping element 120, which is connected to the carrier element 114 and abuts with a clamping region 122 on the side of the membrane element 116 remote from the carrier element 114, so the membrane element 116 is held by clamping between the carrier element 114 and the clamping element 120; and a protection element 124, which is connected to the carrier element 114 and covers the membrane element 116 and the clamping element 120 toward an exterior 126 of the housing 102, so a mechanical influence from outside the housing 102 on the membrane element 116 is prevented by the protection element 124.

As can best be seen from FIGS. 2 and 3, the carrier element 114 comprises a, for example, substantially hollow cylindrical, gas through-channel 128, which, when the pressure compensation device 112 is in the assembled state, preferably extends at least partially into the interior 104 of the housing 102.

The gas through-channel 128 surrounds a, for example substantially circular, gas through-opening 130, through which the interior 104 of the housing 102 of the electrochemical device 100 has a fluid connection to an interior 132 of the pressure compensation device 112.

A reinforcement structure 131, which may, in particular, comprise a central ring 133, which is held by a plurality of, for example, four, struts 135 on a casing wall of the gas through-channel 128, may be arranged in the gas through-channel 128.

The gas through-opening 130 is covered by the membrane element 116.

The membrane element 116 comprises a, for example, substantially circular, membrane 134, which is gas-permeable and is deformable depending on a change of the internal pressure in the interior 104 of the housing 102.

The membrane 134, may, in particular, comprise a porous plastics material and is preferably substantially completely formed from a porous plastics material of this type.

The plastics material may, for example, comprise a fluoropolymer material, and in particular consist substantially completely of a fluoropolymer material.

It is particularly favorable if the membrane comprises a polytetrafluoroethylene material and/or a polytetrafluoroethylene compound and is preferably substantially completely formed from one of the materials mentioned.

A polytetrafluoroethylene compound is to be taken to mean a mixture here of a polytetrafluoroethylene material and one or more fillers.

The term polytetrafluoroethylene (PTFE) in this description and the accompanying claims also designates, in this case, modified polytetrafluoroethylene materials, in which some of the fluorine atoms of the polytetrafluoroethylene are replaced by substituents.

A porous gas-permeable and water pressure-resistant membrane 134 made of a PTFE material or a PTFE compound may be produced in particular, by a granulate of PTFE material or a PTFE compound being pressed and sintered in a cylindrical mould. A peeled film is produced from the sintered cylinder thus obtained, in that the cylinder is made to carry out a rotary movement and a peeling knife is fed against the outer surface of the cylinder. The membrane 134 can be separated, in particular cut out or stamped out, from the peeled film thus obtained.

The membrane element seat 118 of the carrier element 114, on which the membrane element 116 rests (preferably substantially flat), is surrounded by an annular ring protrusion 136 projecting toward the clamping element 120.

The ring protrusion 136 of the carrier element 114 engages in an annular groove 140, which is preferably configured in a substantially complementary manner to the ring protrusion 136, on the side of the clamping element 120 facing the carrier element 114.

The clamping element 102, which is, in particular, formed as a clamping ring 142, furthermore comprises a preferably substantially hollow-cylindrical gas through-channel 144, which is formed and arranged substantially coaxially with respect to the centre axis 138 of the pressure compensation device 112 and substantially coaxially to the gas-through opening 130 and the gas through-channel 128 of the carrier element 114 and substantially coaxially to the membrane 134 of the membrane element 116.

The clamping element 120 and/or the carrier element 114 is preferably formed from a plastics material, in particular as a plastics material injection-molded part.

The clamping element 120 and/or the carrier element 114, may, in particular, be formed from a thermoplastics material or a thermosetting plastics material.

In particular, the clamping element 120 and/or the carrier element 114 may comprise a polypropylene material, a polyethylene material, and/or a polyamide material.

The clamping element 120 and the carrier element 114 may basically be fixed to one another in any manner in order to clamp the membrane element 116 between them.

The clamping element 120 and the carrier element 114 may be releaseably or non-releaseably connected to one another.

For example, it may be provided that the clamping element 120 and the carrier element 114 are integrally connected to one another, in particular by adhesion and/or by welding.

The clamping element 120 and the carrier element 114, may, in particular, be connected to one another by ultrasonic welding or by laser welding.

Alternatively or in addition to this, it may be provided that the clamping element 120 and the carrier element 114 are connected to one another by clipping or latching or screwing.

At the side of the carrier element 114, which is remote from the clamping element 120 and with which the carrier element 114, when the pressure compensation device 112 is in the assembled state, abuts on the outside of the housing wall 108 of the housing 102, the carrier element 114 is provided with an annular sealing element 146, which annularly surrounds the gas through-channel 128 of the carrier element 114.

The sealing element 146, may, in particular, be configured as an O-ring, which is at least partially arranged in an annular groove 150 provided on the carrier element 114.

The sealing element 146 is preferably formed from an elastomer material, in particular from an elastomeric plastics material.

As is, furthermore, best to be seen from FIGS. 1 and 2, the carrier element 114 is provided, preferably radially outside the sealing element 146, with one or more fastening flanges 152, of which each has at least one fastening device receiver 154. Each of the fastening element receivers 154 is used to receive a respective fastening device (not shown), for example a fastening screw, by means of which the pressure compensation device 112 is fastenable, preferably releaseably, to the housing 102 of the electrochemical device 100.

On its side remote from the housing wall 108 when the pressure compensation device 112 is in the assembled state, the carrier element 114 is furthermore provided with an annular holding projection 156, which projects along the direction of the centre axis 138 and cooperates with an also annular holding portion 158 of the protection element 124 in order to hold the protection element 124 on the carrier element 114.

In this case, the protection element 124 and the carrier element 114 may be releaseably or non-releaseably connected to one another.

The protection element 124 preferably comprises a plastics material and may, in particular, be formed as a plastics material injection-molded part.

The protection element 124 preferably comprises a thermoplastics material and/or a thermosetting plastics material.

In particular, the protection element 124 may comprise a polypropylene material, a polyethylene material and/or a polyamide material.

The protection element 124 may, for example, be integrally connected to the carrier element 114, in particular by adhesion and/or by welding.

In particular, the protection element 124 may be connected by ultrasonic welding and/or laser welding to the carrier element 114.

Alternatively or in addition to this, it may also be provided that the protection element 124 is connected to the carrier element 114 by clipping, latching and/or screwing.

The protection element 124 may in particular, be configured as a lid or a cap and may have a substantially dome-shaped form. The protection element 124 extends starting from the holding portion 158, on which the protection element 124 is connected to the carrier element 114, across the central region of the carrier element 114, the clamping element 120 and the membrane element 116, so these components of the pressure compensation device 112 are protected by the protection element 124 from a mechanical influence from the exterior 126 of the housing 102 of the electrochemical device 100.

In order to allow a passage of gas from the interior 132 of the pressure compensation device 112 into the exterior 126, the wall of the protection element 124 is provided with one or more, for example ten, gas through-openings 160, as can best be seen from FIG. 1.

If a plurality of gas through-openings 160 are provided on the protection element 124, these are preferably distributed substantially equidistantly along the periphery of the protection element 124.

A protective degassing element 164 projects into the interior 132 of the pressure compensation device 112 from a central region 162 of the protection element 124, which is intersected by the centre axis 138 of the pressure compensation device 112.

The protective degassing element 164, may, in particular, be configured as a protective degassing spike 166, which ends at a tip 168.

The tip 168 of the protective degassing element 164 opposes the membrane 134 at a predetermined spacing d (when the membrane 134 is in the rest state).

The protective degassing element 164 preferably extends along the centre axis 138 of the pressure compensation device 112. The tip 168 of the protective degassing element 164 preferably lies on the centre axis 138 of the pressure compensation device 112.

Depending on the size of the desired spacing d between the tip 168 of the protective degassing element 164 and the membrane 134, the central region 162 of the protection element 124, on which the protective degassing element 164 is arranged, is formed as a recess (as in the embodiment shown) or as a land (not shown) in the lid-shaped or cap-shaped protection element 124.

To prevent direct access from the gas through-openings 160 of the protection element 124 to the membrane 134, it may be provided that an annular projection 170, which extends from the protection element 124 into the interior 132 of the pressure compensation device 112, is provided on the protection element 124 radially inwardly from the gas through-openings 160.

The annular projection 170 preferably extends in the direction of the centre axis 138 to the axial position of the edge 172 of the gas through-openings 160 of the protection element 124 located closest to the carrier element 114.

It is furthermore preferably provided that the annular projection 170 on the protection element 124 and the gas through-channel 144 of the clamping element 120 overlap one another in the direction of the centre axis 138 so gas from the region of the membrane 134 has to flow in a zigzag course predetermined by the gas through-channel 144 and the annular projection 170 through the interior 132 of the pressure compensation device 112 to the gas through-openings 160 in order to arrive from the pressure compensation device into the exterior 126.

The pressure compensation device 112 described above functions as follows:

During normal operation of the electrochemical device 100, the pressure compensation device 112 allows a pressure compensation between the interior 104 of the housing 102 of the electrochemical device 100, on the one hand, and the exterior 126 of the housing 102, on the other hand.

For this purpose, gas, in particular air, can arrive from the interior 104 of the housing 102 through the gas through-channel 128 of the carrier element 114 with the gas through-opening 130, through the porous, gas-permeable membrane 134, through the part of the interior 132 of the pressure compensation device 112 located on the side of the membrane 134 remote from the carrier element 114 and through the gas through-openings 160 in the protection element 124 into the exterior 126 or, in the reverse direction, from the exterior 126 into the interior 104 of the housing 102.

This makes reliable pressure compensation through the pressure compensation device 112 possible during pressure fluctuations caused by the environment.

The membrane 134 has adequate gas permeability and water pressure resistance for the pressure compensation and protects the interior 104 of the housing 102 from the penetration of dust and water.

The membrane 134 is constructed adequately strongly to avoid an unintended failure of the membrane 134 by water pressure loading from the outside.

If, on the contrary, in a malfunction, for example in the event of failure of one of the electrochemical cells 106 in the interior 104 of the housing 102, a high excess pressure is produced in the interior 104 of the housing 102 (for example by the escape of electrolyte gases, such as HF or H₂, from one of the electrochemical cells 106), the membrane 134 bulges owing to this pressure loading in the direction of the protective degassing element 164 and impinges on the tip 168 of the protective degassing element 164.

The tip 168 of the protective degassing element 164 inflicts preliminary damage on the membrane 134 which, within a very short time (within a few milliseconds) leads to the failure and to the destruction of the membrane 134, so an adequately large cross-section of the gas through-opening 134 is no longer blocked by the membrane 134, but is opened for protective degassing.

The bursting pressure, at which the membrane 134 is damaged by the protective degassing element 164, can be adjusted individually and within narrow limits by a suitable selection of the spacing d between the protective degassing element 164 and the membrane 134 when the membrane 134 is in the rest state.

A second embodiment of a pressure compensation device 112 shown partially in FIG. 8 differs from the first embodiment shown in FIGS. 1 to 7 in that the protective degassing element 164 is not fixed at an invariably predetermined spacing from the membrane 134 on the protection element 124, but the protective degassing element 164 is instead provided with an adjusting thread 172, which cooperates with a thread 174 that is complementary thereto on the protection element 124 in such a way that the position of the protective degassing element 164 relative to the protection element 124 (and therefore also relative to the membrane 134 in the rest state) can be changed in the direction of the central axis 138 in that the adjusting thread 172 of the protective degassing element 164 is screwed to a greater or less extent into the thread 174 of the protection element 124.

It may, in particular, be provided, in this case, that the adjusting thread 172 is configured as an external thread and the thread 174 is configured as an internal thread that is complementary thereto.

Consequently, the spacing d between the tip 168 of the protective degassing element 164 and the membrane 134, and therefore the bursting pressure, at which the membrane 134 bulging forward owing to a pressure increase in the interior 104 of the housing 102 to the protective degassing element 164 comes into contact with the tip 168 of the protective degassing element 164 and is damaged thereby, can be easily set or adjusted.

The second embodiment of the pressure compensation device 112 shown in FIG. 8 therefore comprises a mechanism 176 to change the relative position between the protective degassing element 164 and the membrane 134 when the membrane 134 is in the rest state.

While in the first embodiment shown in FIGS. 1 to 7, the protective degassing element 164 is preferably formed in one piece with the protection element 124 and is preferably formed from a plastics material, in the second embodiment, the protective degassing element 164 may be formed from a material that is different from the material of the protection element 124.

It may thus be provided, for example, that the protective degassing element 164 in the second embodiment comprises a metallic material and, is preferably formed substantially completely from a metallic material.

Otherwise, the second embodiment shown in FIG. 8 of the pressure compensation device 112 coincides with respect to structure, mode of functioning and mode of production with the first embodiment shown in FIGS. 1 to 7, to the above description of which reference is to this extent made.

Both in the first embodiment shown in FIGS. 1 to 7 and in the second embodiment shown in FIG. 8 of the pressure compensation device 112, it may alternatively be provided that the membrane element 116 is not fastened by clamping between the carrier element 14 and the clamping element 120 in the pressure compensation device 112, but, instead, the carrier element 114 and the clamping element 120 are formed in one piece with one another and the membrane element 116 has the material of the carrier element 114 injected around it on its periphery, so that the membrane element 116 and the carrier element 114 are integrally connected to one another.

This can be effected, in particular, in that the membrane element 116 is placed in an injection-molding tool and has the material of the carrier element 114 injected around it. 

1. A pressure compensation device for compensating an internal pressure in a housing of an electrochemical device, comprising at least one gas through-opening and at least one membrane element with a gas-permeable membrane, which is deformable depending on a change in the internal pressure and by which the gas through-opening is blocked, the pressure compensation device comprising a protective degassing element, which is configured and arranged in such a way that when a critical deformation of the membrane is reached, it damages the membrane in such a way that the membrane at least partially opens the gas through-opening for a protective degassing of the housing.
 2. The pressure compensation device according to claim 1, wherein the membrane comprises a porous plastics material.
 3. The pressure compensation device according to claim 1, wherein the membrane comprises a fluoropolymer material.
 4. The pressure compensation device according to claim 1, wherein the pressure compensation device comprises a carrier element and a clamping element, the membrane element being held by clamping between the carrier element and the clamping element.
 5. The pressure compensation device according to claim 4, wherein the carrier element and the clamping element are integrally connected to one another.
 6. The pressure compensation device according to claim 5, wherein the carrier element and the clamping element are latched to one another.
 7. The pressure compensation device according to claim 1, wherein the pressure compensation device comprises a carrier element, in the material of which the membrane element is at least partially embedded.
 8. The pressure compensation device according to claim 1, wherein the pressure compensation device is fixable by means of at least one fastening device on the housing of the electrochemical device.
 9. The pressure compensation device according to claim 8, wherein the pressure compensation device has at least one fastening flange with at least one fastening device receiver for a fastening device.
 10. The pressure compensation device according to claim 1, wherein the pressure compensation device comprises at least one sealing element for sealing between the pressure compensation device and the housing of the electrochemical device.
 11. The pressure compensation device according to claim 1, wherein the pressure compensation device comprises at least one protection element, by which an outside of the membrane is protected from mechanical damage from outside the pressure compensation device.
 12. The pressure compensation device according to claim 11, wherein the protection element has at least one gas through-opening.
 13. The pressure compensation device according to claim 1, wherein the pressure compensation device comprises at least one mechanism for changing the relative position between the protective degassing element and the membrane.
 14. The pressure compensation device according to claim 13, wherein the mechanism for changing the relative position comprises an adjusting thread provided on the protective degassing element.
 15. Use of a pressure compensation device for compensating an internal pressure in a housing of an electrochemical device, wherein the pressure compensation device comprises at least one gas through-opening, at least one membrane element with a gas-permeable membrane, which is deformable depending on a change in the internal pressure and by which the gas through-opening is blocked, and a protective degassing element, which is configured and arranged in such a way that when a critical deformation of the membrane is reached, it damages the membrane in such a way that the membrane at least partially opens the gas through-opening for a protective degassing of the housing, in an electrochemical device, which comprises a housing and a plurality of electrochemical cells arranged in the housing, the pressure compensation device being arranged on the housing.
 16. An electrochemical device, comprising a housing, one or more electrochemical cells arranged in the housing and at least one pressure compensation device arranged on the housing for compensating an internal pressure in the housing of the electrochemical device, wherein the pressure compensation device comprises at least one gas through-opening, at least one membrane element with a gas-permeable membrane, which is deformable depending on a change in the internal pressure and by which the gas through-opening is blocked, and a protective degassing element, which is configured and arranged in such a way that when a critical deformation of the membrane is reached, it damages the membrane in such a way that the membrane at least partially opens the gas through-opening for a protective degassing of the housing. 